Start with the problem
Choosing a tankless heater starts with how the home uses hot water. List the showers and appliances likely to run together, then have the installer assess the equipment and supply requirements. Ask about venting, drainage, electrical or gas work, and service access before settling on a model.
When to ask for help
- Planning an on-demand conversion
- Replacing an unsuitable tankless unit
- A renovation changing hot-water demand
What the plumber needs to check
Peak simultaneous flow and incoming water conditions influence sizing. Existing gas or electrical connections may need assessment before equipment is selected.
How should I prepare?
List the fixtures expected to run together and the proposed equipment location. Ask about venting, condensate handling, service access, and any required approvals.
Before you agree to the work
Compare a complete tankless installation with a storage-tank alternative. Include connection upgrades and maintenance needs instead of comparing appliance prices alone.
What should I decide before buying the heater?
Confirm the proposed model with the installer and get the complete installation scope. A unit bought before those checks may not fit the available supply, space, or household demand.
How to arrange the next step
- Describe the issue, property location, and any immediate safety concern.
- Ask the provider to confirm that they handle the job at your address.
- Check the visit charge and agree on any repair before it begins.
- Keep the findings and ask what was checked when the work was finished.
For Oregon provider checks, use our license and scope guide. This website does not perform plumbing work or guarantee a provider match.
Questions about tankless water heater installation
Can a tankless unit use the old heater’s connections unchanged?
Sometimes, but capacity, compatibility, venting, and installation instructions need checking first.
Will it eliminate the wait at a distant faucet?
Not by itself. Pipe length and any circulation system affect delivery time.
Related homeowner guide
Water heater: repair or replace? — Before buying a new heater, find out what failed and compare the complete cost of each option.
General service guidance · Updated 2026-10-02 · How we prepare our content
